ASTM A471-02

Standard Specification for Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels

SCOPE
1.1 This specification covers vacuum-treated alloy steel forgings intended for use as turbine rotor disks and wheels.
1.2 The values stated in inch-pound units are to be regarded as the standard.

General Information

• Status: Historical
• Publication Date: 09-Sep-2002
• ICS: 77.140.85 - Iron and steel forgings
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.06 - Steel Forgings and Billets

Relations

• Replaces: ASTM A471-94(1999) - Standard Specification for Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels
• Effective Date: 10-Sep-2002
• Replaced By: ASTM A471-05 - Standard Specification for Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels
• Effective Date: 01-Sep-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A 471 – 02
Standard Specification for
Vacuum-Treated Alloy Steel Forgings for Turbine Rotor
1
Disks and Wheels
This standard is issued under the fixed designation A 471; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* 4.2 Vacuum Degassing:
4.2.1 The molten steel shall be vacuum treated prior to or
1.1 This specification covers vacuum-treated alloy steel
during the pouring of the ingot, in order to remove objection-
forgings intended for use as turbine rotor disks and wheels.
able gases, particularly hydrogen.
1.2 The values stated in inch-pound units are to be regarded
6
4.2.1.1 When the vacuum stream degassing process is
as the standard.
used,thevacuumsystemmustbeofsufficientcapacitytoeffect
2. Referenced Documents
a blank-off pressure low enough (usually less than 1000 µm) to
break up the normal tight, rope-like stream of molten metal
2.1 ASTM Standards:
into a wide-angled conical stream of relatively small droplets.
A 275/A 275M Test Method for Magnetic Particle Exami-
2
The capacity of the system must also be sufficiently high to
nation of Steel Forgings
reduce the initial surge pressure at the start of the pour to a low
A 370 Test Methods and Definitions for MechanicalTesting
3
level within 2 min.
of Steel Products
6
4.2.1.2 When the vacuum-lift process is utilized, the mol-
A 388/A 388M Practice for Ultrasonic Examination of
2
tenmetalshallberepeatedlydrawnintotheevacuatedvesselto
Heavy Steel Forgings
give a recirculation factor (Note 1) of at least 2.5 to ensure
E 30 Test Methods for Chemical Analysis of Steel, Cast
4
thorough degassing and mixing of the entire heat. The evacu-
Iron, Open-Hearth Iron, and Wrought Iron
ation system shall be capable of reducing the pressure surges,
E 139 Practice for Conducting Creep, Creep-Rupture, and
5
which occur each time a new portion of steel is admitted to the
Stress-Rupture Tests of Metallic Materials
vessel, to increasingly lower levels until a blank-off pressure
3. Ordering Information
(usually less than 1000 µm) is achieved.
3.1 The purchaser shall specify in the inquiry and order the
NOTE 1—The recirculation factor is obtained as follows:
class of steel desired and test and purchase options (see 4.5.5,
tons of steel lifted per cycle 3 number of cycles
5.2.2, 6.1, 6.3, 7, and 15.1).
heat weight in tons
3.2 Forging Drawing—Each forging shall be manufactured
4.2.1.3 When the ladle degassing process is used, the
in accordance with a purchaser-supplied drawing showing the
evacuation system shall be capable of reducing the system
finished dimensions and the locations of mechanical test
vacuum pressure to a low level (usually less than 1000 µm).
specimens.
The molten metal shall be adequately stirred for a sufficient
3.3 Supplementary requirements are provided and shall
length of time to maximize exposure to the evacuated atmo-
apply only when specified in the purchaser’s order.
sphere. When this process is used, hydrogen testing per
4. Materials and Manufacture Supplemental Requirement S2 is mandatory.
4.2.1.4 Other methods of degassing may be used if the
4.1 Melting Process—The steel shall be made by one or
supplier can demonstrate their adequacy to the satisfaction of
more of the following processes: electric-arc, electric-
the purchaser.When other processes are used, hydrogen testing
induction, or consumable-electrode.
per the supplemental requirement S2 is mandatory.
4.3 Discard—Sufficient discard shall be taken from each
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
ingot to secure freedom from pipe and undue segregation in the
Stainless Steel, and RelatedAlloys, and is the direct responsibility of Subcommittee
finished forging.
A01.06 on Steel Forgings and Billets.
Current edition approved September 10, 2002. Published June 2003. Originally
published as A 471 – 62 T. Last previous edition A 471 – 94 (1999).
2
Annual Book of ASTM Standards, Vol 01.05.
3 6
Annual Book of ASTM Standards, Vol 01.03. Details of the vacuum stream degassing process may be found in the Journal
4
Annual Book of ASTM Standards, Vol 03.05. of the Iron and Steel Institute, Vol 191, January 1959; “Vacuum Pouring of Ingots
5
Annual Book of ASTM Standards, Vol 03.01. for Heavy Forgings” by J. H. Stoll.
*A Summary of Changes section appears at the end of this standard.
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A 471–02
4.4 Forging Process—The forgings shall receive their hot 4.6 Machining:
mechanica
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